RESUMO
Magnetic proximity-induced magnetism in paramagnetic LaNiO3 (LNO) has spurred intensive investigations in the past decade. However, no consensus has been reached so far regarding the magnetic order in LNO layers in relevant heterostructures. This paper reports a layered ferromagnetic structure for the (111)-oriented LNO/LaMnO3 (LMO) superlattices. It is found that each period of the superlattice consisted of an insulating LNO-interfacial phase (five unit cells in thickness, â¼1.1 nm), a metallic LNO-inner phase, a poorly conductive LMO-interfacial phase (three unit cells in thickness, â¼0.7 nm), and an insulating LMO-inner phase. All four of these phases are ferromagnetic, showing different magnetizations. The Mn-to-Ni interlayer charge transfer is responsible for the emergence of a layered magnetic structure, which may cause magnetic interaction across the LNO/LMO interface and double exchange within the LMO-interfacial layer. This work indicates that the proximity effect is an effective means of manipulating the magnetic state and associated properties of complex oxides.
RESUMO
Objective To gain an in-depth understanding of the motivations,patterns,and related factors in family decision-making regarding the referral of terminal patients in tertiary hospitals. Methods Using purposive sampling,terminal patients and their family members from three tertiary hospitals in Beijing were selected as subjects.Semi-structured interviews were conducted,and the interview data were subjected to thematic analysis. Results Following the saturation principle,a total of 11 patients and 15 family members were included.The interview data were organized and analyzed,yielding six major themes:decision premises,decision patterns,family support,support from the referring hospital's medical team,referral channel conditions,and involvement of volunteer teams and social support.Based on these findings,a flowchart illustrating the family decision-making process for the referral of terminal patients was constructed. Conclusions The study provides a comprehensive analysis of various factors influencing family decision-making in the referral of terminal patients in tertiary hospitals.The results underscore the significance of internal and external factors,emphasizing the integrated impact of decision patterns,family support,medical team support,referral channel conditions,and the involvement of volunteer teams and social support.The research offers profound insights into improving the referral process for terminal patients and enhancing the quality of family decision-making.It provides valuable recommendations for future improvements in medical services and decision support.
Assuntos
Tomada de Decisões , Família , Encaminhamento e Consulta , Centros de Atenção Terciária , Humanos , Família/psicologia , Feminino , Masculino , Assistência Terminal/psicologia , Pessoa de Meia-Idade , Apoio Social , AdultoRESUMO
The poor dewaterability of fermented sludge is an important factor limiting the development of anaerobic fermentation applications. Herein we reported an efficient strategy, i.e., using acidic regulation to stimulate the release of indigenous enzymes, to enhance the hydrolysis and dewatering of fermented sludge. The results showed that after acidic regulation at pH 4.0 for 1 day, the activity of protease and α-glucosidase were improved by 131.4% and 146.0%, while the capillary suction time and specific resistance to filtration were decreased by 93.8% and 69.5%, respectively. Mechanism study revealed that the method firstly destroyed the slime and bound EPS and cells of fermented sludge, causing the release of indigenous enzymes (i.e., protease and α-glucosidase) contained in. Then, the released enzymes directly accelerated the hydrolysis and acidification of fragmentized extracellular polymeric substances, thereby benefited the release of bound water in sludge particles. Finally, such acidic condition decreased the electrostatic repulsive interactions between destroyed sludge particles, further improving their flocculation. The findings not only deepen the understanding of indigenous enzymes contained in fermented sludge affecting sludge dewatering, but also might guide engineers to develop promising strategies to facilitate fermented sludge dewatering and fermentation liquid recovery in the future.
Assuntos
Esgotos , alfa-Glucosidases , Esgotos/química , Hidrólise , Filtração , Ácidos/química , Água/química , Peptídeo Hidrolases , Eliminação de Resíduos Líquidos/métodosRESUMO
Spin structure of a magnetic system results from the competition of various exchange couplings. Pressure-driven spin structure evolution, through altering interatomic distance, and hence, electronic structure produces baromagnetic effect (BME), which has potential applications in sensor/actuator field. Here, we report a new spin structure(CyS-AFMb) with antiferromagnetic(AFM) nature in Fe-doped Mn0.87Fe0.13NiGe. Neutron powder diffraction (NPD) under in situ hydrostatic pressure and magnetic field was conducted to reveal the spin configuration and its instabilities. We discovered that a pressure higher than 4 kbar can induce abnormal change of Mn(Fe)-Mn(Fe) distances and transform the CyS-AFMb into a conical spiral ferromagnetic(FM) configuration(45°-CoS-FMa) with easily magnetized but shortened magnetic moment by as much as 22%. The observed BME far exceeds previous reports. Our first-principles calculations provide theoretical supports for the enhanced BME. The compressed lattice by pressure favors the 45°-CoS-FMa and significantly broadened 3d bandwidth of Mn(Fe) atoms, which leads to the shortened magnetic moment and evolution of spin structure.
RESUMO
Primary ciliary dyskinesia (PCD) is an autosomal recessive genetic disease. Gene mutation leads to ciliary structural abnormalities or functional defects, resulting in respiratory diseases. Male patients with PCD are prone to infertility, which pathogenically may be attributed to gene mutation-induced dysfunction of respiratory cilia and sperm flagella. This reviews focuses on the research progress in microtubule structure, gene mutation and outcomes of assisted reproduction relating to PCD complicated by male infertility.
RESUMO
IgG4-related retroperitoneal fibrosis is a type of IgG4-related diseases. The etiology is still unclear. It is often classified as idiopathic retroperitoneal fibrosis, but the pathological process and clinical results between them are different. Therefore, the differential diagnosis of them is very important. An 18-year-old patient was admitted to the Second Xiangya Hospital of Central South University due to "left lower extremity edema for 1 and a half month" on December 19, 2019. In examination of PET/CT, the starting point of the left aorta-intra-thoracic artery showed a soft tissue density lump with increased sugar metabolism, which indicated a suspected malignant tumor, and dilatation of the left renal pelvis and ureter. On January 8, 2020, the patient was performed pelvic edema excision, ureterectomy and anastomosis. The postoperative examination results were considered as IgG4-related disease. As a rare systemic disease, early correct diagnosis and precise and individualized treatment can alleviate the suffering of patients and ensure that patients are minimally traumatized.
Assuntos
Fibrose Retroperitoneal , Adolescente , Edema/diagnóstico , Edema/etiologia , Humanos , Imunoglobulina G/uso terapêutico , Extremidade Inferior/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Fibrose Retroperitoneal/complicações , Fibrose Retroperitoneal/diagnóstico , Fibrose Retroperitoneal/tratamento farmacológicoRESUMO
OBJECTIVE: Endocrine dysfunction caused by pituitary abscess (PA) and its outcomes have not been fully studied. This study aims to investigate endocrine dysfunction and outcomes in patients with PA. METHODS: Eight patients (3 males and 5 females) with PA were identified for collecting clinical, hormone, and therapeutic data before and after long-term follow-up lasting 12 to 116 months (median, 25 months) since the first hospitalization, which was regarded as the baseline time. All patients' pituitary and respective target gland functions were evaluated. Six patients had acute onset (less than 1 month), and the other 2 patients had chronic onset (more than 6 months). Five patients underwent surgical therapy, and the other 3 patients underwent conservative therapy. The factors associated with endocrine outcome were analyzed as well. RESULTS: At baseline, the release of 91.7% (22 of 24 total) of pituitary tropic hormones was impaired, but 59.1% (13 of 22) had normalized by the last follow-up. Male gender, acute onset mode, and normal baseline prolactin level seemed to be the factors that favored tropic hormone normalization, whereas surgical operation was not. Two patients received provocative test suggesting decreased reserves of both somatotrophin and prolactin or only somatotrophin. Only 1 patient suffered from permanent diabetes insipidus. CONCLUSION: The production of almost all pituitary tropic hormones was impaired with PA in the present study, but production of nearly 60% percent of the hormones normalized during follow-up of >1 year. A chronic abscess state may be the most important factor associated with permanent hormone deficiency.
Assuntos
Abscesso/fisiopatologia , Doenças da Hipófise/fisiopatologia , Hipófise/fisiopatologia , Abscesso/terapia , Hormônio Adrenocorticotrópico/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Doenças da Hipófise/terapia , Hormônios Hipofisários/biossíntese , Estudos RetrospectivosRESUMO
Aortic dissection is a life-threatening emergency. Well-established risk factors include systemic hypertension, hereditary connective tissue diseases (Marfan syndrome and Ehlers-Danlos syndrome), coarctation of the aorta, bicuspid aortic valve, aortitis, and arch hypoplasia. Ischemia of the viscera, the kidneys, the spinal cord, or the lower extremities due to malperfusion constitutes life-threatening complications that have to be considered in the treatment strategy.We report a rare case of symptomatic ischemia of the lower extremities due to aortic dissection. This case demonstrates that the treating physician needs to be vigilant for ischemia reperfusion injuries such as osteofascial compartment syndrome and acute renal failure in aortic dissection.
Assuntos
Aneurisma Aórtico/terapia , Dissecção Aórtica/terapia , Procedimentos Endovasculares , Traumatismo por Reperfusão/etiologia , Adulto , Dissecção Aórtica/complicações , Aneurisma Aórtico/complicações , Humanos , Masculino , Traumatismo por Reperfusão/diagnósticoRESUMO
OBJECTIVE: To evaluate the safety and efficacy of scrotoscope in diagnosis and treatment of testicular and epididymal diseases. METHODS: From September 2010 to March 2012, a total of 75 patients, aged 15-64 years (mean age is 42.4 years) were included in this study. Based on ultrasonagraphy before surgery, 12 cases were diagnosed as testicular torsion and 63 cases were diagnosed as epididymal mass. All the patients underwent scrotoscope examination or scrotoscope epididymectomy. A small scrotal incision of 1.0 cm was performed. Bluntly dissection was then performed through the scrotal layer until the tunica sac was disclosed. We used cystoscope or resectoscope as scrotoscope. Keeping the drip fusion of isotonic solution inflowing, the scrotum was maintained appropriate distended. The tunica sac wall including parietal and visceral tunica was checked. The testis, epididymis was then examined from the anterior, posterior and both lateral aspects to find out any potential pathology. The operation time of scrotoscope, postoperative complications, surgery record, ultrasound and pathology results were collected from medical record. Visual analog pain scale (range from 0 points to 10 points, 0 represent no pain, 10 represent the most severe pain) was used to assess scrotal pain. The postoperative complications, recurrence and pain relief were evaluated, the accuracy rates of the diagnosis was compared between scrotoscope and ultrasound based on pathology results. RESULTS: All the patients were successfully performed scrotoscope except one because of inflammatory adhesion. The average time of the operation was 34.3±5.8 minutes, and no serious complications, such as severe edema, hematoma, testicular hydrocele and wound infection occurred. The accuracy rate of scrotoscope and ultrasound for the diagnosis of testicular torsion was 100% vs. 66.7%, and the accuracy rate of scrotoscope and ultrasound for the diagnosis of epididymal mass was 76.2% vs. 58.7%. In the study, 63 patients received scrotoscope epididymectomy, the visual analogue pain score before surgery was 7.1±0.8, 6 months after operation, and the pain score was 2.4±0.6. CONCLUSION: Scrotoscope is safe. There are no serious complications such as severe edema, hematoma, testicular hydrocele and wound infection occurred. Scrotoscope is superior to ultrasound for diagnosis of testicular torsion and epididymal mass. Scrotoscope epididymectomy is effective for pain relief, especially for patients with epididymal cyst.
Assuntos
Doenças dos Genitais Masculinos/diagnóstico , Escroto , Procedimentos Cirúrgicos Urológicos Masculinos/instrumentação , Adolescente , Adulto , Epididimo/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Dor , Medição da Dor , Complicações Pós-Operatórias , Próstata , Recidiva , Torção do Cordão Espermático/diagnóstico , Testículo , Procedimentos Cirúrgicos Urológicos Masculinos/métodos , Ducto Deferente , Adulto JovemRESUMO
Bladder interstitial cell (IC) is a cell, which lacks thick filaments and dense bodies but with incomplete basement membrane, rough endoplasmic reticulum and golgi apparatus. IC is divided into 4 subtypes: lamina propria IC, intramuscular IC, IC between the detrusor bundles and perivascular IC. There are different ion currents and related activation pathways in the lamina propria IC and intramuscular IC. Ca2+ signaling pathways play an important role in the communication between IC and detrusor. Any bladder lesions affecting the ion current and Ca2+ signaling pathways can lead to bladder dysfunction. The bladder lesions include bladder outlet obstruction, bladder pain syndrome, interstitial cystitis, neurogenic bladder and diabetes. Imatinib mesylate is currently an available treatment target in IC, and electrical stimulation of acupuncture therapy is a new direction.
Assuntos
Cistite Intersticial/patologia , Mucosa/patologia , Benzamidas , Estimulação Elétrica , Humanos , Mesilato de Imatinib , Piperazinas , Pirimidinas , Transdução de SinaisRESUMO
OBJECTIVE: To look into the effects of different anesthesia methods on the labor process and the expression of serum estrogen and progesterone in primiparas with painless labor. METHODS: 60 primiparas receiving painless labor were selected as the research objects, and they were divided into either a Spinal & Continuous epidural anesthesia group (n = 30) or a continuous epidural anesthesia group (n = 30), anesthesia is administered using the corresponding anesthesia method. The authors compared serum estrogen and progesterone, inflammatory index expression, pain degree and neonatal health status in different periods. RESULTS: At T2 and T3, serum P, LH, FSH and E2 levels in the Spinal & Continuous epidural anesthesia group were signally lower than those in the Spinal & Continuous epidural anesthesia group (p < 0.05). Spinal & Continuous epidural anesthesia group harbored faster onset and longer duration of sensory block and motor block than the Continuous epidural anesthesia group (p < 0.05). SAS and SDS scores of the Spinal & Continuous epidural anesthesia group were clearly lower than those of the Continuous epidural anesthesia group (p < 0.05). VAS score and serum TNF-α, IL-6 levels of pregnant women in the Spinal & Continuous epidural anesthesia group were memorably lower than those in the Continuous epidural anesthesia group at T2 and T3 (p < 0.05). The total incidence of postoperative complications in the Spinal & Continuous epidural anesthesia group was distinctively lower than that in the Continuous epidural anesthesia group (p < 0.05). CONCLUSION: Spinal anesthesia combined with continuous epidural anesthesia has a better anesthesia effect in the painless labor of primiparas, which can effectually ameliorate the labor process and the expression of serum estrogen and progesterone.
Assuntos
Anestesia Epidural , Estrogênios , Período Pós-Parto , Progesterona , Humanos , Feminino , Gravidez , Progesterona/sangue , Anestesia Epidural/métodos , Adulto , Estrogênios/sangue , Período Pós-Parto/sangue , Trabalho de Parto/sangue , Raquianestesia/métodos , Anestesia Obstétrica/métodos , Adulto Jovem , Fatores de Tempo , Medição da Dor , Paridade , Interleucina-6/sangue , Fator de Necrose Tumoral alfa/sangueRESUMO
Koji-making is a key process for production of high quality soy sauce. The microbial composition during koji-making was investigated by culture-dependent and culture-independent methods to determine predominant bacterial and fungal populations. The culture-dependent methods used were direct culture and colony morphology observation, and PCR amplification of 16S/26S rDNA fragments followed by sequencing analysis. The culture-independent method was based on the analysis of 16S/26S rDNA clone libraries. There were differences between the results obtained by different methods. However, sufficient overlap existed between the different methods to identify potentially significant microbial groups. 16 and 20 different bacterial species were identified using culture-dependent and culture-independent methods, respectively. 7 species could be identified by both methods. The most predominant bacterial genera were Weissella and Staphylococcus. Both 6 different fungal species were identified using culture-dependent and culture-independent methods, respectively. Only 3 species could be identified by both sets of methods. The most predominant fungi were Aspergillus and Candida species. This work illustrated the importance of a comprehensive polyphasic approach in the analysis of microbial composition during soy sauce koji-making, the knowledge of which will enable further optimization of microbial composition and quality control of koji to upgrade Chinese traditional soy sauce product.
Assuntos
Bactérias/isolamento & purificação , Contagem de Colônia Microbiana/métodos , Fungos/isolamento & purificação , Glycine max/microbiologia , Reação em Cadeia da Polimerase/métodos , Alimentos de Soja/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Biodiversidade , Fermentação , Fungos/classificação , Fungos/genética , Fungos/metabolismo , Dados de Sequência MolecularRESUMO
The neuroimaging results of drug-resistant epilepsy patients play an important role in the surgery decision and prognosis. The aim of this study was to evaluate the impact of these results on the efficacy of epilepay surgery, and then to explore surgical benefit for epilepsy patients with negative magnetic resonance (MR) images. Twenty-four subgroups describing the outcomes of 1475 epilepsy patients with positive-neuroimaging results and 696 patients with negative-neuroimaging results were involved in the meta-analysis. Overall, the odds of postoperational seizure-free rate were 2.03 times higher in magnetic resonance imaging-positive (MRI-positive) patients than in MRI-negative patients [odds ratio (OR)=2.03, 95% CI (1.67, 2.47), P<0.00001]. For patients with temporal lobe epilepsy (TLE), the odds were 1.76 times higher in those with MRI-positive results than in those with MRI-negative results [OR=1.76, 95% CI (1.34, 2.32), P<0.0001]. For patients with extra-temporal lobe epilepsy (extra-TLE), the odds were 2.88 times higher in MRI-positive patients than in MRI-negative patients [OR=2.88, 95% CI (1.53, 5.43), P=0.001]. It was concluded that the seizure-free rate of MRI-positive patients after surgery was higher than that of MRI-negative patients. For patients with negative results, an appropriate surgery should be concerned for TLE.
Assuntos
Epilepsia/diagnóstico , Epilepsia/cirurgia , Imageamento por Ressonância Magnética/estatística & dados numéricos , Procedimentos Neurocirúrgicos/estatística & dados numéricos , Cirurgia Assistida por Computador/estatística & dados numéricos , China/epidemiologia , Epilepsia/epidemiologia , Humanos , Prevalência , Prognóstico , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Resultado do TratamentoRESUMO
This study aimed to compare the predictive value of six selected anthropometric indicators for benign prostatic hyperplasia (BPH). Males over 50 years of age who underwent health examinations at the Health Management Center of the Second Xiangya Hospital, Central South University (Changsha, China) from June to December 2020 were enrolled in this study. The characteristic data were collected, including basic anthropometric indices, lipid parameters, six anthropometric indicators, prostate-specific antigen, and total prostate volume. The odds ratios (ORs) with 95% confidence intervals (95% CIs) for all anthropometric parameters and BPH were calculated using binary logistic regression. To assess the diagnostic capability of each indicator for BPH and identify the appropriate cutoff values, receiver operating characteristic (ROC) curves and the related areas under the curves (AUCs) were utilized. All six indicators had diagnostic value for BPH (all P ≤ 0.001). The visceral adiposity index (VAI; AUC: 0.797, 95% CI: 0.759-0.834) had the highest AUC and therefore the highest diagnostic value. This was followed by the cardiometabolic index (CMI; AUC: 0.792, 95% CI: 0.753-0.831), lipid accumulation product (LAP; AUC: 0.766, 95% CI: 0.723-0.809), waist-to-hip ratio (WHR; AUC: 0.660, 95% CI: 0.609-0.712), waist-to-height ratio (WHtR; AUC: 0.639, 95% CI: 0.587-0.691), and body mass index (BMI; AUC: 0.592, 95% CI: 0.540-0.643). The sensitivity of CMI was the highest (92.1%), and WHtR had the highest specificity of 94.1%. CMI consistently showed the highest OR in the binary logistic regression analysis. BMI, WHtR, WHR, VAI, CMI, and LAP all influence the occurrence of BPH in middle-aged and older men (all P ≤ 0.001), and CMI is the best predictor of BPH.
Assuntos
Hiperplasia Prostática , Pessoa de Meia-Idade , Masculino , Humanos , Idoso , Obesidade/epidemiologia , Índice de Massa Corporal , China/epidemiologia , Razão Cintura-Estatura , Curva ROC , Circunferência da Cintura , Fatores de RiscoRESUMO
Phytoplankton community characteristics, diversity, and functional group analysis can respond to the environmental quality status of water bodies. To investigate the influence of urban river black odors on the phytoplankton community, from November 2020 to March 2021, 16 urban rivers in the Sichuan Basin were surveyed for water quality with 38 sampling points, and the degree of urban river black odor was evaluated based on the improved fuzzy mathematical model method and the k-mean principal color extraction method. The rivers were classified into four types:non-black and non-odorous, black and non-odorous, black and odorous, and black and odorous. The results showed that, with black and odorous water, the phytoplankton abundance increased from 1.329×105 cells·L-1 to 6.627×105 cells·L-1, and the dominant phytoplankton phylum decreased from Cyanophyta-Chlorophyta-Bacillariophyta to Cyanophyta. The phytoplankton biomass increased from 64.056 µg·L-1 to 120.465 µg·L-1, and the dominant phytoplankton phylum changed from Chlorophyta-Bacillariophyta type, adapted to a nutrient environment, to Pyrrophyta-Bacillariophyta-Cryptophyta type, adapted to an organic matter environment. The Shannon-Weaver diversity index decreased from 2.45 to 1.98, and Simpson's index decreased from 0.84 to 0.73. Twenty nine functional groups of phytoplankton were observed in the study area, and the growth strategy was reduced from S, R, C, CR, and CS to R with black and odorous water. In summary, phytoplankton indicators can better reflect the state of river black odor, and phytoplankton monitoring is a promising tool for urban river black odor management.
Assuntos
Diatomáceas , Dinoflagellida , Fitoplâncton , Odorantes , RiosRESUMO
Oxygen evolution reaction (OER) and urea oxidation reaction (UOR) play important roles in the field of hydrogen energy preparation and pollution treatment. In this work, by merging bimetallic Co-Mo oxides with metallic Co on the graphite felt (GF), we effectively manufacture a 3D bifunctional and highly efficient electrocatalyst (CoMoO@Co/GF) with multi-site functionality for the simultaneous reduction of water and the oxidation of urea in an alkaline medium. The presence of metallic Co causes Co-Mo oxides to evolve from amorphous to crystalline structures. The coupling interface produced between metallic Co and Co-Mo oxides is proven to facilitate electron transport in addition to extensively accessible and highly electroactive Co-Mo oxide nanoflower architecture. The experimental results reveal that the overpotentials for OER and UOR in the CoMoO@Co/GF electrode require only 269 and 115 mV to obtain a current density of 10 mA cm-2, respectively. Furthermore, with the aid of urea, the overpotential for HER at the current density of 10 mA cm-2 is lowered to 155 mV. Most notably, the constructed CoMoO@Co/GF-based electrolytic cell only requires a 1.5 V dry battery to achieve effective H2 evolution and noteworthy stability, outperforming the commercial catalyst-based device and many previous results. The combination of experiments and theoretical calculations further clarifies the active sites in the catalyst. What's more, the pathway of electron transfer in the catalytic process is defined.
RESUMO
Lignin, a biological resource with great potential, can be as high as â¼16% of the total organics in the waste activated sludge (WAS). This work therefore aims to fill the knowledge gap about the effect of lignin on short-chain fatty acids (SCFAs) production from anaerobic fermentation of sludge. Experimental results showed that lignin promoted rather than inhibited SCFAs production. Specifically, the presence of 15% lignin promoted the SCFAs production from 129.1 ± 6.5 to 223.14 ± 7.8 mg COD/g VSS compared with the control, and the proportion of acetic increased by 61.8%, while that of propionic decreased by 44.9%. Mechanism exploration revealed that lignin improved the solubilization of biodegradable substrates due to its hydrophobic characteristics. In addition, lignin enhanced the acidogenesis process, possibly by perfecting the electron transfer chain in the fermentation system, and the quinone structure in lignin may compete electrons with methanogens to inhibit the consumption of SCFAs. Microbiological analysis showed that the abundance of microorganisms related to acidogenesi, especially the acetogenesis, including Proteiniclasticum sp., Acetoanaerobium sp., in the fermenter with lignin increased, which caused the community to shift towards specialized and diverse SCFAs production.
Assuntos
Lignina , Esgotos , Anaerobiose , Ácidos Graxos Voláteis , Fermentação , Concentração de Íons de HidrogênioRESUMO
Unevenly distributed polypyrrole (PPy) films/coatings with extensive "dead volumes" via electrodeposition have emerged as a main challenge for high energy density flexible supercapacitor. In this work, we have fabricated a phytic acid-guided graphite carbon felt/polypyrrole (GF@PA@PPy) 3D porous composite with less "dead volumes" via electrodeposition. After the activation of phytic acid (PA), the quantity and content of defects and oxygen-containing groups on the surface of carbon felt (GF) have increased. First, these functional groups improve the hydrophilicity of the surface of GF, resulting in the preferential uniform distribution of pyrrole monomer (Py). While significantly, the synergistic effects between the defects and oxygen-containing groups boost the attraction of pyrrole ring, and thus promotes the formation of perfect PPy films with less "dead volume" on GF. Finally, the supercapacitor assembled from the GF@PA@PPy-40 displays a high areal energy density of 0.0732 mWh cm-2, exceeding the previously reported PPy-based electrodes values. The deeper understanding of the role for the defects and oxygen-containing groups in the synthesis of PPy/carbon materials offers a new strategy to construct advanced PPy-based supercapacitors.
Assuntos
Polímeros , Pirróis , Galvanoplastia , Ácido FíticoRESUMO
MOF-derived multi-metal nanomaterials are attracting numerous attentions in widespread applications such as catalysis, sensors, energy storage and conversion, and environmental remediation. Compared to the monometallic counterparts, the presence of foreign metal is expected to bring new physicochemical properties, thus exhibiting synergistic effect for enhanced performance. MOFs have been proved as a good platform for the fabrication of polymetallic nanomaterials with requisite features. Herein, various design strategies related to constructing multi-metallic nanomaterials from MOFs are summarized for the first time, involving metal nodal substitution, seed epitaxial growth, ion-exchange strategy, guest species encapsulation, solution impregnation and combination with extraneous substrate. Afterwards, the recent advances of multi-metallic nanomaterials for electrocatalytic applications, including oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), are systematically discussed. Finally, a personal outlook on the future trends and challenges are also presented with hope to enlighten deeper understanding and new thoughts for the development of multi-metal nanomaterials from MOFs.
Assuntos
Estruturas Metalorgânicas , Nanoestruturas , Catálise , Estruturas Metalorgânicas/química , Metais , Nanoestruturas/química , Oxigênio/química , Estudos ProspectivosRESUMO
With the increasing serious water pollutions, an increasing interest has given for the nanocomposites as environmental catalysts. To date, noble metals-based nanocomposites have been extensively studied by researchers in environmental catalysis. In detail, serving as key functional parts, noble metals are usually combined with other nanomaterials for rationally designing nanocomposites, which exhibit enhanced catalytic properties in pollutants removal. Noble metals in the nanocomposites possess tailored properties, thus playing different important roles in catalytic oxidation reactions for pollutants removal. To motivate the research and elaborate the progress of noble metals, this review (i) summarizes advanced characterization techniques and rising technology of theoretical calculation for evaluating noble metal, and (ii) classifies the roles according to their disparate mechanism in different catalytic oxidation reactions. Meanwhile, the enhanced mechanism and influence factors are discussed. (iii) The conclusions, facing challenges and perspectives are proposed for further development of noble metals-based nanocomposites as environmental catalysts.